[PATCH 1/3] NFS: Have decode_pnfs_layout_types() use XDR's decode_uint32_array()

[Anna Schumaker <anna@kernel.org>]

From: Anna Schumaker <anna.schumaker@hammerspace.com>

Rather than hardcoding in an alternative that doesn't properly check for
32-bit overflow during decoding.

Signed-off-by: Anna Schumaker <anna.schumaker@hammerspace.com>
---
 fs/nfs/nfs4xdr.c | 33 +++++++++------------------------
 1 file changed, 9 insertions(+), 24 deletions(-)

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 740f3bc4a19d..4d12b97f423e 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -4924,32 +4924,17 @@ static int decode_getfattr(struct xdr_stream *xdr, struct nfs_fattr *fattr,
 static int decode_pnfs_layout_types(struct xdr_stream *xdr,
 				    struct nfs_fsinfo *fsinfo)
 {
-	__be32 *p;
-	uint32_t i;
+	ssize_t nlayouttypes;
 
-	p = xdr_inline_decode(xdr, 4);
-	if (unlikely(!p))
-		return -EIO;
-	fsinfo->nlayouttypes = be32_to_cpup(p);
+	nlayouttypes = xdr_stream_decode_uint32_array(xdr,
+						      fsinfo->layouttype,
+						      NFS_MAX_LAYOUT_TYPES);
+	if (nlayouttypes == -EMSGSIZE)
+		nlayouttypes = NFS_MAX_LAYOUT_TYPES;
+	if (nlayouttypes < 0)
+		return nlayouttypes;
 
-	/* pNFS is not supported by the underlying file system */
-	if (fsinfo->nlayouttypes == 0)
-		return 0;
-
-	/* Decode and set first layout type, move xdr->p past unused types */
-	p = xdr_inline_decode(xdr, fsinfo->nlayouttypes * 4);
-	if (unlikely(!p))
-		return -EIO;
-
-	/* If we get too many, then just cap it at the max */
-	if (fsinfo->nlayouttypes > NFS_MAX_LAYOUT_TYPES) {
-		printk(KERN_INFO "NFS: %s: Warning: Too many (%u) pNFS layout types\n",
-			__func__, fsinfo->nlayouttypes);
-		fsinfo->nlayouttypes = NFS_MAX_LAYOUT_TYPES;
-	}
-
-	for(i = 0; i < fsinfo->nlayouttypes; ++i)
-		fsinfo->layouttype[i] = be32_to_cpup(p++);
+	fsinfo->nlayouttypes = nlayouttypes;
 	return 0;
 }
 
-- 
2.56.0